Abstract A simulation to predict DNA damages due to 114.2 MeV/u carbon ions and 62 MeV protons at different depths was performed by a new approach to make a comparison between those different beams. An atomic model of DNA was used to build the different levels of DNA organization in the cell nucleus. A new damage diagnostic algorithm was designed to identify break yields and has been used with the Geant4 toolkit. The single strand break (SSB) ratios for carbon ions compared to proton were 18.5 and 19 at 5 mm and 30.7 mm depth in water respectively. For Double-Strand Breaks (DSBs) the ratios were higher and they varied from 27 at 5 mm to 55 at the Bragg peak depth. The DSB yields for the same depths of carbon ion and proton beams were evaluated. The results indicated that the entrance DSB yield were 0.84 and 1.19 (GyGbp)-1 (at 5 mm depth) for protons and carbon ions, respectively, while at the Bragg peak depth were 1.15 and 3.11 (GyGbp)-1. It has been found that the DSB yield at 5 mm for the carbon beam was about 1.4 times higher than for the proton beam and regarding the Bragg peak depth, this ratio was 2.7. Our new damage diagnostic algorithm can help the identification of breaks. Also, results confirmed that carbon ions are more effective in biological effects than protons.

中文翻译：

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使用 Geant4-DNA 通过碳离子和质子的新方法计算直接 DNA 损伤

摘要 通过一种新方法对不同深度的 114.2 MeV/u 碳离子和 62 MeV 质子造成的 DNA 损伤进行了模拟预测，以比较这些不同的光束。DNA 的原子模型用于在细胞核中构建不同层次的 DNA 组织。设计了一种新的损坏诊断算法来识别断裂产量，并已与 Geant4 工具包一起使用。与质子相比，碳离子的单链断裂 (SSB) 比在水中 5 毫米和 30.7 毫米深度分别为 18.5 和 19。对于双链断裂 (DSB)，比率更高，从 5 毫米处的 27 到布拉格峰深度处的 55。对相同深度的碳离子和质子束的 DSB 产率进行了评估。结果表明，入口 DSB 收率分别为 0.84 和 1。质子和碳离子分别为 19 (GyGbp)-1（5 毫米深度），而布拉格峰深度为 1.15 和 3.11 (GyGbp)-1。已经发现，碳束在 5 mm 处的 DSB 产率比质子束高约 1.4 倍，关于布拉格峰深度，该比率为 2.7。我们新的损坏诊断算法可以帮助识别断裂。此外，结果证实碳离子在生物效应方面比质子更有效。